Electronic and Ionic Conduction in Sodium Borosilicate Glasses

Electron and sodium ion motion in sodium borosilicate glasses containing Sb2O3 has been determined by thermally stimulated polarization and depolarization current (TSPC/TSDC) technique. Whereas a glass containing Sb2O3 exhibited a TSPC peak, the peak was absent in a similar glass without Sb2O3. The TSPC peak which appeared in TSPC-1 and TSPC-2 was 103-104 times larger than the TSDC peaks and had an activation energy higher than that of the TSDC peaks and ionic dc conduction. Electron hopping between Sb5+ and Sb3+ ion sites is considered responsible for the TSPC peak. All the glasses show two TSDC peaks. The origin of the low temperature TSDC peak is uncertain but the high temperature TSDC peak could be accounted for by the orientation of Na+ ions around [BO4]- groups. Above ~ 360 K the dc conduction is due to sodium ion motion